This invention relates to a combustion safety apparatus for preventing occurrence of an accident caused by lack of oxygen.
As for an apparatus of this kind, there has been hitherto known such a type one that an oxygen concentration in combustion exhaust gas of a burner is monitored by an oxygen concentration cell element such as zirconia or the like, so that when the oxygen concentration in the combustion exhaust gas is lowered as a result of incomplete combustion of the burner made at the time of lack of oxygen, a safety valve interposed in a gas supply pipe is closed by an output of the element. It can be considered, in this type of apparatus, that in order that combustion exhaust gas may be securedly brought into contact with the element, a detecting tube for introducing the combustion exhaust gas is provided, and that the element formed as a tubular element is interposed in the detecting tube. In this arrangement, it is desirable that the combustion exhaust gas should flow in a stable condition through the detecting tube.